HACKENSACK — Thirteen police dogs and handlers graduated Friday after logging 500 hours of training as part of the Bergen County Sheriff’s Office scent detection class, honing their ability to seek out drugs and explosives.

Dogs have become an important asset for local law enforcement, specifically as the county battles a jump in the heroin abuse, Bergen County Prosecutor John L. Molinelli said.

“It never ceases to amaze me how we can train a beautiful, four-legged animal to be of such assistance,” Molinelli said.

Bergen County Sheriff Michael Saudino said demand for the dogs has increased in recent years and pointed to major busts where K-9 units were key to a successful arrest.

“Just in Bergen County, our K-9 units have been coming up with multiple bricks of heroin and oxycodone,” Saudino said.

In another case, a sheriff’s officer and his K-9 partner nabbed an accused bank robber late last year.

Eleven dogs were trained in narcotics detection while three were taught to sniff out explosives in the program. Graduates included five teams from the Bergen County Sheriff’s Office, one from the Fort Lee Police Department as well as state park police, federal park police and two from the Union County Sheriff’s Office.

John Reuter, a Fort Lee police officer who served as academy class president, described the grueling eleven-week training regime that pushed the teams through everything from injuries and bad weather.

“I had no idea how difficult it would be before starting training,” Reuter said before graduating with his German Shepard, Ajax.

Sheriff’s Office Inspector Mickey Bradley, a certified K-9 expert, said energetic dogs always ready to play are the best fit for scent training.

“The difficult part is finding a dog with the drive,” he said. “It has to want to do this morning, noon and night.”